In a communications network, such as the Internet, for example, there is often a need for a network device, such as a server, to be able to remotely access a remote device on the network, such as a STB located in a person's home. In particular, there is a need for Internet Protocol (IP)—enabled STBs (IPSTBs) to be accessible asynchronously (i.e., in real-time) from a service platform (SP) in the Internet. The Internet SP needs to be able to asynchronously access the IPSTB for a number of reasons, including, for example, allowing a remote subscriber operating from a cell phone or personal computer (PC) to obtain immediate access to content on their IPSTB for digital video recorder (DVR) programming, content pull, etc.
Typically, an IPSTB in the home resides behind a router that implements a configuration known as Network Address Translation (NAT). An Internet Service Provider may also impose NAT and firewall functionality in its network to block asynchronous Internet access to a subscriber's IPSTB. The NAT inherently prevents an Internet SP from accessing the IPSTB unless a NAT address binding is established in the router between the Internet SP and the IPSTB. The NAT address binding includes IP address and User Datagram Protocol (UDP) or Transmission Control Protocol (TCP) port mapping between the Internet SP on the Wide Area Network (WAN) side of a router and the IPSTB on the Local Area Network (LAN) side of the router.
A NAT address binding can be established and maintained by a periodic LAN-to-WAN side transmission of “keep-alive” message packets sent from LAN-side IPSTB to the WAN-side Internet SP. The keep-alive messages must exchanged frequently enough to keep the NAT address binding alive. If the exchanges are not sent frequently enough, the NAT IP/port address binding entry timer will timeout, and the Internet SP will not be able to access the IPSTB. This problem is compounded by the fact that different routers may have different timeout values for NAT IP/port address binding entries. Thus, in order to ensure that a NAT entry is kept alive, the keep-alive messages are typically sent more frequently than is absolutely necessary; often as short as the shortest NAT IP/port address binding timeout period. This frequent transmission of keep-alive messages consumes a large amount of network bandwidth when averaged over many IPSTBs sending such messages.
A need exists for a way to allow a network device, such as an Internet SP, for example, to asynchronously access an IPSTB that is efficient in terms of network bandwidth consumption.